Magnetic cell stirrer

ABSTRACT

This specification discloses several embodiments of the basic concept of providing a magnetic stirrer for a container of cells which is characterized by the inclusion of a magnet that is mounted on the lower end of a shaft which is mounted on or in a closure for an opening in the top of the container in such a manner that when magnetic forces are applied to the magnet from a rotating magnet external of the bottom of the container the magnet on the shaft is rotated, and, due either to the construction of the shaft which in most of the embodiments is flexible, or to its mounting on the closure, will move radially outwardly and upwardly in the container under the influence of the centrifugal force generated by its rotation. In the flexible shaft embodiments provision is made for adjusting the flexing amplitude of the shaft. Provision is also made for the introduction of a fluid, either gaseous or liquid, into the container through the closure and in addition to the culture or other material which is being stirred.

United States Patent [:91

Balas MAGNETIC CELL STIRRER [75] Inventor: John Thomas Balas, Vineland,NJv

{73] Assignee: Wheaton Industries, Millville, NJ.

[22] Filed: Sept. 12, I974 [2|] Appi. No.: 505,226

Related US. Application Data [62] Division of Ser, No. 379,081, July l3,1973, Pat. No

[52] US. Cl. l. 259/21; 2S9/DIG. 46; 259/1 [8 [5 1] Int. Cl. ..B01Fl3/08;BO1F 7/30 (58] Field of Search 259/ll6, 117, H8, H9, 259/121, [22,I25, I02, DIG. 46, 21, 22, 23, 24, 5, 64

[56] References Cited UNITED STATES PATENTS 2.932.493 4/1960 Jacobs259/102 3,245,665 4/1966 Steel 259/DlG, 46

Primary ExaminerR0bert W. Jenkins Attorney, Agent, or FirmEric P.Schellin Aug. 19, 1975 57 ABSTRACT This specification discloses severalembodiments of the basic concept of providing a magnetic stirrer for acontainer of cells which is characterized by the inclusion of a magnetthat is mounted on the lower end of a shaft which is mounted on or in aclosure for an opening in the top of the container in such a manner thatwhen magnetic forces are applied to the magnet from a rotating magnetexternal of the bottom of the container the magnet on the shaft isrotated. and, due either to the construction of the shaft which in mostof the embodiments is flexible, or to its mounting on the closure, willmove radially outwardly and upwardly in the container under theinfluence of the centrifugal force generated by its rotation. In theflexible shaft embodiments provision is made for adjusting the flexingamplitude of the shaft Provision is also made for the introduction of afluid, either gaseous or liquid. into the container through the closureand in addition to the culture or other material which is being stirred.

2 Claims, 9 Drawing Figures PATENTED AUG-1 9 I975 SHEET 1 UF 3 PATENTEUAUG-1 91975 3. 900.186

' sum 3 nr 3 MAGNETIC CELL STIRRER This is a division of applicationSer. No. 379,081, filed July 13 I973, now US Pat. No. 3,854,704

The present invention relates to magnetic culture flasks for cellculture, for clinical mixing, fluid dispersion and the like and isconcerned primarily with a magnetic stirrer which includes, as acharacteristic and basic element, a flexible or rigid shaft carrying acoated magnet at its lower end.

BACKGROUND OF THE INVENTION At the present time magnetic stirrers forcultures are known. Devices of this type which are now availablecomprise a flask having a flat bottom which rests on a magneticoperator. The operator includes a magnet which is rotated from asuitable power source. The flask also includes a top wall in which isjournalled a vertical shaft having a magnet at its lower end, having itspolarity related to the polarity of the magnetic operator so thatrotation of the latter causes rotation of the magnet in the flask. Inthese known devices, the position of the magnetic stirrer is fixedrelative to the flask bottom and walls. Thus, it can rotate only in thisfixed position and the position of the magnetic stirrer relative to theflask bottom and flask wall never varies. This fixation is decidedlimitation on the effectiveness of the stirring action. In thisjoumalled design sometimes the bearing jams, causing the unit to stopresulting in damage or loss of flask contents.

Also with the magnetic stirrer fixed in a position closely adjacent tothe flask bottom it is impossible to stir the contents of the upperportion of the flask without disturbing any materials which may havecollected on the bottom.

OBJECTS OF THE INVENTION With the foregoing conditions in mind, thepresent invention has in view the following objectives:

1. To provide a magnetic stirrer for cells and the like for a containerof a non-magnetic material which includes a bottom and a top opening andwhich stirrer comprises a closure for the opening, a flexible shaftmounted in the closure and a coated rigid magnet at the lower end of theshaft that is slightly spaced from the bottom of the container when thestirrer is assembled therewith.

2. To provide, in a container for stirring cells and the like of thetype noted, a flexible shaft together with means for adjusting theflexing amplitude of the shaft.

3. To provide, in a container for stirring cells and the like of thecharacter aforesaid, a flexible shaft having means associated therewithfor introducing a fluid into the container through the closure.

4. To provide, in a container for stirring cells and the like of thekind described, a hollow flexible shaft which projects above the closureand is provided with a fitting for charging gas or other fluidstherethrough with the lower end portion of the shaft adjacent to themagnet having discharge openings through which gas or other fluids isemitted into the culture; and

5. To provide in a container for stirring cells and the like of the typenoted, a rigid shaft that is connected at its upper end to a closure .orthe container by a gimbal bearing and has a coated magnet secured to itslower end.

Various other more detailed objects and advantages of the invention,such as arise in connection with carrying out the above ideas in apractical embodiment, will, in part, become apparent and, in part, behereafter stated as the description of the invention proceeds.

SUMMARY OF THE INVENTION The foregoing objects are achieved by providinga flask comprising a substantially flat bottom, a wall upstanding fromthe bottom and a top wall including a neck defining an opening withwhich is associated a closure. This closure ordinarily takes the form ofa stopper although a screw cap or other devices may be used. Mounted inthis stopper is a flexible shaft which may be solid but is preferrablytubular. For the smaller and intermediate size flasks, this' shaft mayextend above the stopper an appreciable distance to provide flexibilityto a required degree. An insert of appreciable rigidity, is insertedinto the tubular shaft and is adjustable therein, whereby the presenceand longitudinal location of the insert determines the flexingamplitude. For larger size bottles, a rigid shaft of suitable materialmay be mounted in the stopper and the flexible member may be secured tothe lower end thereof. In this embodiment a similar flexing amplitudeadjustment may be employed providing both rigid and flexible shafts aretubular.

When it is desired to introduce a liquid into the flasks, a rigid tubemay be mounted in the stopper, either vertical or at an offset angle. Asuspension rod has its upper end secured to this tube and the flexibleshaft is attached to the lower end thereof.

When gas or other fluid substances is to be introduced into the flask afitting is provided for introducing gas or fluid substance into theflexible tube above the stopper and the lower end of the tube adjacentto the magnet has a plurality of openings through which gas isdischarged into the culture.

For a full and more complete understanding of the invention, referencemay be made to the following description and the accompanying drawingswherein:

FIG. 1 is a perspective of a container for stirring cells and the likeembodying the precepts of this invention and designed for smaller andintermediate sized flasks with a portion of the flask br -ken away.

FIG. 2 is a detailed sectional showing of the stopper, flexible shaft,and magnet.

FIG. 3 is a detailed sectional showing of the embodiment for larger sizeflasks which includes a rigid shaft.

FIG. 4 is a detailed perspective illustrating a screw cap which may beemployed in lieu of a stopper.

FIG. 5 is a perspective of a modification by which liquids areintroduced into flasks through the stopper.

FIG. 6 is a fragmentary sectional view of the embodiment of FIG. 5.

FIG. 7 is a detailed elevation of a modification for introducing gas orother fluid substance into the culture.

FIG. 8 is a perspective of a modification including a rigid shaft thatis connected at its upper end to the container closure and carries acoated magnet at its lower end; and

FIG. 9 is an elevation of the stopper, gimbal bearing, shaft and magnet,with movement of the shaft and magnet being depicted in broken lens.

Before referring to the drawings, reference is made to US. Pat. No.3,572,651, which discloses a spinculture flask for cell culture and moreparticularly, illustrates the magnet operating mechanism for activatingthe magnet within the flask. Referring now to the drawings, and firstmore particularly, to FIGS. 1 and 2, a container for stirring cells andthe like for smaller and intermediate sizes will be described. In thisconnection it is noted that the intermediate sized may range between 125and 500 milliliters in volume. The smaller sizes are those which areless than 125 milliliters, and the larger sizes are those having acapacity in excess of 500 milliliters.

A flask is referred to in its entirety at 10. It may be of anyappropriate material, such as glass or plastic. Flask comprises a bottom11 which is substantially flat, a cylindrical wall 12, and a top 13which includes a neck 14 that defines an opening 15. As shown in FIG. 1opening 15 is provided with a closure in the form of a stopper 16 havinga central vertical passage 17.

In this connection, it is noted that the present invention will bedescribed with the stopper 16 closing the opening 15. However, it willbe understood that this opening 15 might be closed by screw cap, such asshown at 18 in FIG. 4, or other suitable devices.

Rotatably mounted in passage I7 is a flexible shaft 19. While the shaft19 may be of any material having the required property of strength andflexibility, tetrafluoroethylene polymer or tetrafiuorethylene-hexafluoropropylene copolymer is indicated as a preferred material. Also,while shaft 19 may be solid, it is shown as being tubular presenting abore 20. Mounted on the lower end of shaft 19 is a coated magnet 21.Magnet 21 comprises a bar magnet presenting a pole at 22 which is coatedwith a material which is inert with respect with the culture or materialwhich is to be stirred in glass 10. Pole 22 is located closely adjacentto bottom 11 from which magnet 21 is spaced a slight distance.

In the case of the smaller size flasks such as those having a diameterless than 125 milliliters, shaft 19 may project above the upper face ofstopper 16 an appreciable distance. This extent of the shaft 19 lendsthe property of flexibility thereto to the degree which may be requiredin small size flasks.

When the magnet operating mechanism of the above identified patent isoperated, the magnetic force thereof is effective on pole 22 of magnet21 to cause the latter to rotate in the manner depicted by the arrows inFIG. 1. This rotation generates centrifugal force which causes themagnet 21 to swing outwardly and upwardly and thus provide a highlyeffective area and space in which the stirring action takes place.

As shown in FIG. 2, an insert 23 is positioned into bore of shaft 19 andpresents a lower end 24 which determines the flexing amplitude of shaft19. Thus, shaft 19 will ordinarily not flex above end 24. It is intendedthat by adjusting insert 23 in bore 20 the flexing amplitude may beadjusted.

It is believed that in most conditions of use of the smaller sizeflasks, the insert 23 will not be required. However, it may beincorporated into such smaller size flasks if so desired.

Referring now to FIG. 3, a rigid tube 25 is shown as rotatably mountedin passage 17 of stopper [6. Tube 25 may be of metal or glass or othersuitable material and attached to the lower end thereof in any preferredmanner, such as by an adhesive is a flexible shaft section 26. The usualmagnet 21 is mounted at the lower end of shaft section 26. In operationthe amplitude of flexing is determined by the lower end of shaft 25.However, should it be desired to shorten this ampli tude, insert 23 maybe positioned through shafts 25 and 26 until its lower end 24 is at adesired position to determine the flexing amplitude.

Referring now more particularly to FIGS. 5 and 6, a stopper 27 is usedto close the opening 15 rather than the stopper l6. Stopper 27 is formedwith a passage 28 which is inclined with respect to the vertical.Mounted in passage 28 is a tube 29 which is of a rigid material such asglass. Tube 29 has open ends 30 and 31 with the opening end 30 beingclosed when required by plug 32 or other suitable means. A rigidsuspension member 33 has one end secured to tube 29 at 34. This point ofconnection at 34 is located on the vertical axis of flask 10. A flexibleshaft 35 is rotatably mounted on the lower end of suspension member 33as indicated at 36, the lower end of flexible shaft 35 carries the usualcoated magnet 21.

FIG. 6 shows the flask 10 as including a culture or other material 37which is to be stirred. Should it be desired to add a liquid to thisculture plug 32 is removed and the liquid poured through tube 29.

FIG. 7 illustrates the modification by which gas or other fluids may beintroduced into the culture. Thus, stopper 16 has the usual passage 17.Rotatably received in this passage 17 is the upper end portion of aflexible tube 38 which carries a coated magnet (not illustrated) at itslower end. Spaced from this lower end the tube 38 is formed with aplurality of openings 39. Shaft 38 projects above stopper 16 and mountedthereon is a fitting 40 from which a conduit 41 extends. Gas isintroduced through conduit 41 and fitting 40 into shaft 38 from which itis discharged through openings 39 into the culture or other fluid 37.

Referring now to FIGS. 8 and 9, a modification that is characterized bythe inclusion of a rigid shaft will be described. FIG. 8 shows acontainer 10 and a closure in the form of stopper 9. The latter presentsan undersurface 42. Secured to stopper 9 at surface 42 is a gimbalbearing identified in its entirety at 43. The latter comprises a hollowsphere 44 which is formed at its lower region with an opening 45 or arequired size. Universally rotatable in sphere 43 is a ball 46.

A rigid shaft 47 has its upper end anchored to ball 46 as indicated at48. A coated magnet 21 is carried by shaft 47 at its lower end.

As magnet 21 is rotated by the magnetic operator it will swing radiallyand upwardly under centrifugal force. The pattern of such movement isdepicted by broken lines in FIG. 9. The size of opening 45 will dependon how much movement of shaft 47 is to be accommodated.

While preferred specific embodiments are herein disclosed, it is to beclearly understood that the invention is not to be limited to the exactconstructions, devices and materials illustrated and described becausevarious modifications of these details may be provided in putting theinvention into practice.

What is claimed is:

1. For use with a container for stirring cells and the like, saidcontainer including a bottom, a wall upstanding from said bottom, and anopening at the top, a magnetic flexible stirrer comprising:

a. a closure for said opening with a central vertical passage andproportioned for a tight fitting relationship with said opening, saidpassage being offset at an angle with respect to the vertical axis ofthe container and having a rigid tube received in said passage and arigid suspension member having its upper end connected to the rigid tubeand its lower end to a flexible shaft, said connection of the suspensionmember to the rigid tube lying in the vertical axis of the containerwhereby liquid may b. a flexible shaft mounted in said central passagewith said closure between the ends thereof; and

be introduced into said container through said rigid 5' c. a coatedmagnet rigidly mounted on said flexible tube; shaft at the lower endthereof and closely adjacent b. a coated magnet rigidly mounted on saidflexible to the bottom of said container when the stirrer is shaft atthe lower end thereof and closely adjacent assembled therewith, wherebyas said magnet is roto the bottom of said container when the stirrer istated by magnetic operating mechanism the shaft assembled therewith,whereby as said magnet is ro- 10 flexes into an arcuate configurationand moves uptated by magnetic operating mechanism the shaft wardly andoutwardly relative to said bottom by the flexes into an arcuateconfiguration and moves upcentrifugal force generated by such rotationcauswardly and outwardly relative to said bottom by the ing the saidflexure. centrifugal force generated by such rotation causd. theflexible shaft is tubular, projects above the cloing the said flexure. 5sure and is formed with a plurality of openings ad- 2. For use with acontainer for stirring cells and the jacent to the magnet, together witha fitting on the like, said container including a bottom, a wallupstandflexible shaft above the closure and a conduit coning from saidbottom, and an opening at the top, a magnected to said fitting forintroducing gas through netic flexible stirrer comprising: the fittingand into the flexible shaft.

a. a closure for said opening formed with a central

1. For use with a container for stirring cells and the like, saidcontainer including a bottom, a wall upstanding from said bottom, and anopening at the top, a magnetic flexible stirrer comprising: a. a closurefor said opening with a central vertical passage and proportioned for atight fitting relationship with said opening, said passage being offsetat an angle with respect to the vertical axis of the container andhaving a rigid tube received in said passage and a rigid suspensionmember having its upper end connected to the rigid tube and its lowerend to a flexible shaft, said connection of the suspension member to therigid tube lying in the vertical axis of the container whereby liquidmay be introduced into said container through said rigid tube; b. acoated magnet rigidly mounted on said flexible shaft at the lower endthereof and closely adjacent to the bottom of said container when thestirrer is assembled therewith, whereby as said magnet is rotated bymagnetic operating mechanism the shaft flexes into an arcuateconfiguration and moves upwardly and outwardly relative to said bottomby the centrifugal force generated by such rotation causing the saidflexure.
 2. For use with a container for stirring cells and the like,said contAiner including a bottom, a wall upstanding from said bottom,and an opening at the top, a magnetic flexible stirrer comprising: a. aclosure for said opening formed with a central vertical passage andproportioned for a tight fitting relationship with said opening; b. aflexible shaft mounted in said central passage with said closure betweenthe ends thereof; and c. a coated magnet rigidly mounted on saidflexible shaft at the lower end thereof and closely adjacent to thebottom of said container when the stirrer is assembled therewith,whereby as said magnet is rotated by magnetic operating mechanism theshaft flexes into an arcuate configuration and moves upwardly andoutwardly relative to said bottom by the centrifugal force generated bysuch rotation causing the said flexure. d. the flexible shaft istubular, projects above the closure and is formed with a plurality ofopenings adjacent to the magnet, together with a fitting on the flexibleshaft above the closure and a conduit connected to said fitting forintroducing gas through the fitting and into the flexible shaft.